Patient monitoring system

ABSTRACT

A patient monitoring system includes an inflatable cuff, a gas reservoir containing a compressed gas, and a sensor. When the inflatable cuff is coupled to a wearer, the gas reservoir supplies gas to the inflatable cuff to inflate the inflatable cuff via gas pathways. As the inflatable cuff inflates, a patient monitor can receive blood pressure data from the sensor and use the blood pressure data to determine the blood pressure of the wearer. The patient monitor can also receive blood pressure data during deflation of the inflatable cuff to determine the blood pressure of the wearer.

RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. §119(e) toU.S. Provisional Application Nos. 61/499,515, filed Jun. 21, 2011,entitled “Blood Pressure Monitoring System,” and 61/645,570, filed May10, 2012, entitled “Patient Monitoring System,” each of which is herebyincorporated herein in its entirety.

BACKGROUND

Hospitals, nursing homes, and other wearer care facilities typicallyinclude patient monitoring devices at one or more bedsides in thefacility. Patient monitoring devices generally include sensors,processing equipment, and displays for obtaining and analyzing a medicalwearer's physiological parameters such as blood oxygen saturation level,respiratory rate, and the like. Clinicians, including doctors, nurses,and other users, use the physiological parameters obtained from patientmonitors to diagnose illnesses and to prescribe treatments. Cliniciansalso use the physiological parameters to monitor wearers during variousclinical situations to determine whether to increase the level ofmedical care given to wearers. Additionally, monitoring equipment isoften used in corporate care facilities, fitness facilities,recreational and home care applications, as well as mobile or otheremergency care environments.

Blood pressure (which can refer to diastolic pressure, systolicpressure, and/or some combination or mathematical representation ofsame) considered one of the principal vital signs, is one example of aphysiological parameter that can be monitored. Blood Pressure monitoringis an important indicator of a wearer's cardiovascular status. Manydevices allow blood pressure to be measured by manual or digitalsphygmomanometer systems that utilize an inflatable cuff applied to aperson's arm. The term “sphygmomanoter” is meant to receive its ordinarybroad meaning known to an artisan to include devices used to measureblood pressure. These devices often include an inflatable cuff torestrict blood flow and a device capable of measuring the pressure.Other device(s) are used to determine at what pressure blood flow isjust starting and at what pressure it is just unimpeded, commonlyreferred to as “systolic” and “diastolic,” respectively. The term“systolic blood pressure” is meant to receive its ordinary broad meaningknown to an artisan to include the pressure exerted on the bloodstreamby the heart when it contracts, forcing blood from the ventricles of theheart into the pulmonary artery and the aorta. The term “diastolic bloodpressure” is meant to receive its ordinary broad meaning known to anartisan to include the pressure in the bloodstream when the heartrelaxes and dilates, filling with blood.

In a typical pressure monitoring system, a hand actuated pump or anelectric motor inflates the inflatable cuff to a pressure level at orabove the expected systolic pressure of the wearer and high enough toocclude an artery. Automated or motorized blood pressure monitoringsystems use a motor or pump to inflate the inflatable cuff, while manualblood pressure monitors typically use an inflation bulb. As the air fromthe inflatable cuff is slowly released, the wearer's blood pressure canbe determined by detecting Korotkoff sounds using a stethoscope or otherdetection device placed over an artery.

Alternatively, digital sphygmomanometers compute diastolic and systolicpressure as the inflatable cuff deflates based on the oscillationsobserved by a pressure sensor on the cuff. For example, some digitalsphygmomanometers calculate the systolic blood pressure as the pressureat which the oscillations become detectable and the diastolic pressureas the pressure at which the oscillations are no longer detectable.Other digital sphygmomanometers calculate the mean arterial pressurefirst (the pressure on the cuff at which the oscillations have themaximum amplitude). The diastolic and systolic pressures are thencalculated based on their fractional relationship with the mean arterialpressure. Other algorithms are used, such as identifying the change inslope of the amplitude of the pressure fluctuations to calculate thediastolic pressure.

As mentioned above, the foregoing methods of determining blood pressureinclude inflating the cuff to a pressure high enough to occlude anartery and then determining blood pressure during deflation of theinflatable cuff. Occluding the artery and then determining bloodpressure during deflation can have a number of drawbacks. For example,inflating the inflatable cuff to a pressure higher than systolicpressure can cause pain and discomfort to the wearer. Other adverseeffects can include limb edema, venous stasis, peripheral neuropathy,etc, or simply wearer interruption. In addition, as the artery iscompletely occluded prior to each measurement, sufficient time mustelapse between measurements to ensure accurate results. Furthermore,manual systems make it difficult to measure blood pressure duringinflation of the inflatable cuff due to the difficult of inflating theinflatable cuff at an approximately constant rate using an inflationbulb.

Digital blood pressure monitors can have additional drawbacks. Themotors used to pump gas into the cuff are often noisy and can disturbwearers at rest. This is especially problematic in recovery situations.In addition to auditory noise in automated or motorized systems, themotors can cause electrical noise in sensor signals making signalprocessing used to identify reference points for blood pressuredetection unreliable and difficult. Furthermore, portable motorizedblood pressure monitors require a significant amount of power to producethe air pressure required to inflate the cuff. Since batteries are oftenused to provide power, designers often use large batteries and/orbatteries that frequently need to be recharged or replaced. When a largebatter is chosen, its size often offsets the goals of portability as anappropriate housing becomes more cumbersome and less convenient.

SUMMARY

Based on at least the foregoing drawbacks, a need exists for a patientmonitoring system that relatively quickly determines blood pressuremeasurements without necessarily greatly disturbing a patient. Moreover,a need exists for a portable patient monitoring system with batterylongevity. Accordingly, the present disclosure includes embodiments of apatient monitoring system including a gas reservoir filled with asufficient quantity of compressed gas to inflate an inflatable cuff anda sensor to detect blood pressure data. The gas in the gas reservoir caninflate the inflatable cuff at a controlled rate, such as, for example,at an approximately constant rate. Manual and/or electronicallycontrolled regulators and/or valves can be used to control the flow rateof the gas into and out of the inflatable cuff. In some embodiments, theregulators and/or valves can be electronically controlled usingpulse-width modulation (PWM) schemes.

A patient monitor can also be included as part of the patient monitoringsystem. During inflation or deflation of the inflatable cuff, thepatient monitor can receive the blood pressure data from the sensor anduse the blood pressure data to determine output measurements responsiveto the blood pressure of the wearer. The sensor can be a pressure sensorand can be used to detect pressure variations in the inflatable cuff dueto inflation, deflation, and blood flow in an artery of the wearer.Alternatively, the sensor can be an auditory sensor or stethoscope. Acaregiver can use the stethoscope or auditory sensor to determine bloodpressure measurements without the use of the patient monitor.

For purposes of summarizing the invention, certain aspects, advantagesand novel features of the invention have been described herein. Ofcourse, it is to be understood that not necessarily all such aspects,advantages or features will be embodied in any particular embodiment ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments will be described hereinafter with reference to theaccompanying drawings. These embodiments are illustrated and describedby example only, and are not intended to limit the scope of thedisclosure. In the drawings, similar elements have similar referencenumerals.

FIG. 1A is an exemplary block diagram illustrating an embodiment of apatient monitoring system;

FIG. 1B is an exemplary block diagram illustrating an embodiment of gaspathways between different components of the patient monitoring systemof FIG. 1A;

FIG. 2 is an exemplary system diagram illustrating an embodiment of thepatient monitoring system of FIG. 1;

FIGS. 3A-3G illustrate an exemplary embodiment of a patient monitoringsystem configured to be worn by a user;

FIGS. 4A-4C are plot diagrams illustrating embodiments of pressurevariations of an inflatable cuff associated with a wearer during bloodpressure measurement; and

FIGS. 5A and 5B are flow diagrams illustrating embodiments of a processimplemented by a patient monitor for measuring the blood pressure of awearer.

FIG. 6 is a flow diagram illustrating another embodiment of a processimplemented by the patient monitor for measuring blood pressure of awearer.

FIG. 7 is a flow diagram illustrating yet another embodiment of aprocess implemented by the patient monitor for measuring blood pressureof a wearer.

DETAILED DESCRIPTION

A patient monitoring system advantageously includes a gas reservoirfilled with sufficient quantities of compressed gas to inflate aninflatable cuff. The gas reservoir provides several advantages to theblood pressuring monitoring system, including portability, reusability,disposability, reduction in auditory noise and electrical noise, and theability to measure blood pressure during inflation of the blood pressurecuff.

In an embodiment, the gas reservoir of the patient monitoring systeminflates the inflatable cuff at an approximately constant rate with lessauditory noise. By providing a quieter environment, the patientmonitoring system is capable of taking blood pressure measurementswithout significantly disturbing the wearer. In addition, the use of thegas reservoir can significantly reduce the amount of potentiallyinterfering electrical noise on electrical signals from one or moresensors. Furthermore, the addition of the gas reservoir allows thepatient monitor to take blood pressure measurements during inflation ofthe inflatable cuff.

Measuring blood pressure during inflation can reduce the time requiredfor blood pressure measurements and the amount of pressure used. In someembodiments, the patient monitoring system can measure blood pressure in15-20 seconds or less. Furthermore, measuring blood pressure duringinflation can reduce or eliminate the need to occlude a wearer's artery.

In addition, the gas reservoir of the present disclosure can bemanufactured as a smaller portable patient monitor. The gas reservoircan eliminate the need for a pump and/or motor in the portable patientmonitor, thereby reducing its size. In an embodiment, the gas in the gasreservoir can be used to generate electricity for the portable patientmonitor, thereby reducing or eliminating the need for a battery andfurther reducing the size of the portable patient monitor.

In addition to the foregoing, other embodiments of the presentdisclosure include patient monitoring systems with canister inflationand one or more backup inflation systems. For example, in an embodiment,when the patient monitor is for whatever reason without sufficient gasto make a reliable, accurate blood pressure measurement, a motor andpump and/or inflation bulb may advantageously be used in place of thecanister. In an embodiment, the foregoing backup inflation system(s) ispart of the patient monitoring system and is activated when gas from thegas canister is unavailable, unwanted, insufficient, or the like. Forexample, in an embodiment, a user may designate which inflation systemthey would prefer based on, for example, proximity to power, battery usedesires, gas use management, portability, emergency, surgical, othercritical monitoring environments, or the like. In still furtheradditional embodiments, the forgoing backup inflation system(s) areseparate systems that connect to the monitor in place of the canister.

In an embodiment, measurements by a patient monitoring system of thepresent disclosure may be controlled through applications or softwareexecuting on one or more computing devices, such as a smart phone,tablet computer, portable digital devices of all types, or othercomputing devices or systems or combinations of the same. In anembodiment, the computing device may include modules governing themeasurement frequency during periodic measurements. In an embodiment,the applications or software may include exercise related softwareconfigured to use blood pressure measurements to enhance feedback tousers on a performance of the exercise, such as, for example, caloriesspent, heart rate trending or the like. Additionally, inputs may includetype of exercise, user demographics like height, sex, age, weight or thelike. Based on the inputs, the portable digital device can provideexercise recommendations, such as walking, running, cycling or otherphysical activities.

In still additional embodiments of the disclosure, the patientmonitoring system may communicate with electronics of the canister forquality control to ensure it is an authorized canister, for canistercharacteristics information, such as type, pressure, size, manufacturer,or the like. Simultaneously, the monitor may communicate withelectronics of the cuff and or sensors.

In additional embodiments of the disclosure, a patient monitoring systemmay connect to a gas supply supplied at a premises. For example, ahospital or other caregiver environment may have pressurized gasavailable from connection in a room, group of rooms, beds, instruments,or the like and straightforward connection of the monitor to the gassupply may supplement or replace the canister.

In yet another embodiment, a display of a patient monitoring system maypresent measurement data in a manner that reduces a need for translationwhen used by speakers of different languages. For example, the displaymay include icons, numbers, colors, analog style digital gauge icons,such as a dial, gas bar or the like, audible and/or visual alarms,combinations of the same or the like to convey measurement informationto a user or caregiver.

In still further embodiments, the monitor may be entirely portable andconfigured to mount to an arm, wrist, waist or belt harness, carried ina pocket of the like.

Various embodiments will be described hereinafter with reference to theaccompanying drawings. These embodiments are illustrated and describedby example only, and are not intended to be limiting.

FIG. 1 is a block diagram illustrating an embodiment of a patientmonitoring system 100 for measuring blood pressure of a wearer, whichmay also be referred to as taking blood pressure measurements, using aninflatable cuff 104. The patient monitoring system 100 can be used tomeasure the blood pressure of a wearer during inflation, deflation orboth. In an embodiment, the patient monitoring system 100 includes a gasreservoir 102, the inflatable cuff 104 and a patient monitor 106.

The gas reservoir 102 houses compressed gas and is operatively connectedto the inflatable cuff 104 via a gas pathway. In an embodiment, aregulator 103 is in the gas pathway between the inflatable cuff 104 andreservoir 102. In an embodiment, the regulator 103 provides a desiredpressure or flow in the cuff-side so long as there is sufficientpressure on the reservoir side. Thus, gas flows from the gas reservoir102, through the regulator 103 to the bladder of the inflatable cuff104. In one embodiment, the gas pathway is an airtight pathwayconstructed of any number of materials including, but not limited to,metal, plastic, cloth, combinations of the same or some other airtightmaterial.

The gas reservoir 102 can be implemented using one or more disposable orreusable gas tanks, cylinders, bottles, canisters, or cartridges, of anynumber of shapes or sizes, and can be located in the same room as thewearer, or can be remotely located from the wearer, such as in adifferent room or even in a different building. For example, the gasreservoir 102 can include a large gas tank that remains in a stationarylocation. The gas reservoir 102 can be large enough to containsufficient gas for a large number of blood pressure readings (e.g. morethan 100). Furthermore, the gas reservoir 102 can store compressed gasat any number of PSI levels. For example, the gas reservoir can storecompressed gas up to about 6000 PSI or more, depending on the safetyconditions of the environment. Furthermore, the gas tank can beconfigured to supply gas to multiple inflatable cuffs 104, therebylimiting the number of gas tanks used for multiple wearers. When thepressure levels in the gas tank reach a threshold, the gas tank caneither be refilled, replaced or a combination of both. For example arotating cache of gas tanks can be used as the gas reservoir 102.

Alternatively, the gas reservoir 102 can be implemented using a smallgas tank of any number of sizes. For example, the gas reservoir 102 canbe implemented using a gas tank that is small enough to fit in the palmof a hand, such as a carbon dioxide (CO₂) cartridges similar to or thesame as those used for paint ball guns, tire inflation, or the like. CO₂cartridges are available from a number of different manufacturers anddistributors, such as the AirSource 88 Gram Pre-filled Disposable CO₂cartridge available from Crosman (Product Code: CRO-88-GRAM). The PSIlevels for smaller gas tanks can also differ greatly and can storecompressed gas up to about 2000 PSI or more. In one embodiment, the gasreservoir 102 is implemented using a gas tank of compressed gas at about1000 PSI. The small gas reservoir 102 can be used where mobility isdesired. For example, paramedics or first responders can carry a smallgas reservoir 102 for measuring blood pressure of persons needingemergency medical care. Using the gas reservoir 102, the emergencypersonnel (or some other user) can measure the blood pressure of thewearer during inflation of the inflatable cuff, deflation, or acombination of the two. The measurements can be taken using a patientmonitor 106, manually using a stethoscope, or other methods.

In one embodiment, a pressure regulator, or regulator 103, placed at anopening of the gas reservoir 102 controls whether gas can exit the gasreservoir and the amount of gas allowed to exit. In one embodiment, theregulator 103 is a valve. The regulator 103 can also be configured tocontrol the rate at which gas flows to the inflatable cuff 104, as wellas the pressure of the gas or PSI level. The regulator 103 can include asecond regulator near the opening of the gas reservoir 102 or in the gaspathway to form a two-stage pressure regulator. Additional regulatorscan be added as desired. The regulator 103 and/or valve can beimplemented using any number of different valves, such as a globe valve,butterfly valve, poppet valve, needle valve, etc., or any other type ofvalve capable of operating as a variable restriction to the gas flow.Furthermore, the regulator 103 can include a pressure gauge to identifythe pressure levels of the gas exiting the gas reservoir 102 and/or inthe gas pathway.

Using the regulator 103, the inflatable cuff 104 can be inflated at acontrolled rate, such as, for example, an approximately constant rate orlinear rate. By inflating the inflatable cuff at a controlled rate, thewearer's blood pressure can be measured during inflation and withoutoccluding the artery. The regulator 103 can further include a wirelesstransmitter for communication with the patient monitor 106, which inturn may electronically control and/or monitor the flow of gas throughthe regulator 103. Alternatively, the regulator 103 can communicate withthe patient monitor via wired communication. Additionally, the gasreservoir 102 can include a pressure gauge to monitor the remainingpressure and/or the amount of compressed gas remaining in the gasreservoir 102. The pressure gauge can communicate the pressure levels tothe patient monitor 106 via wired or wireless communication, similar tothe regulator 103. Once the pressure gauge indicates a thresholdpressure level or gas level has been reached, the patient monitor 106can indicate that the gas reservoir 102 should be replaced or refilled.

The gas reservoir 102 can contain any number of compressed gases toinflate the inflatable cuff 104. For example, the gas reservoir 102 cancontain compressed air, carbon dioxide, nitrogen, oxygen, helium,hydrogen, etc. Any number of other gases can be used to inflate theinflatable cuff 104. Furthermore, the gas reservoir 102 may house enoughgas to inflate the inflatable cuff 104 without the use of a motor orpump during the inflation. The gas reservoir 102 can be pre-filled withgas near the wearer or at a remote site away from the wearer. In oneembodiment, the gas reservoir 102 is filled with gas prior to beingassociated with the inflatable cuff 104. Pre-filling the gas reservoir102 prior to use can significantly reduce the ambient noise causedduring inflation of the inflatable cuff 104. In addition, by using thegas reservoir 102, the electrical noise from a motor can be removed. Thereduction in ambient and electrical noise and the approximately constantrate of inflation of the inflatable cuff 104 allows the patient monitor106 to measure the wearer's blood pressure while the inflatable cuff 104is inflating. In addition, the gas reservoir 102 can be used to quicklyinflate the inflatable cuff 104 for blood pressure measurements takenduring deflation of the inflatable cuff 104.

In some embodiments, multiple gas reservoirs 102 are included as part ofthe patient monitoring system 100. The multiple gas reservoirs 102 canbe used for backup purposes or for different tasks. For example, a firstgas reservoir 102 can be a large gas reservoir and can be used to supplygas to the inflatable cuff 104 when the user is stationary. A secondoptionally smaller gas reservoir 102 can also be provided. When the usermoves away from the first gas reservoir 102, the first gas reservoir canbe disconnected from the inflatable cuff 104 and the second gasreservoir 102 will supply the gas to the inflatable cuff 104. In certainembodiments, a pump may be connected to the inflatable cuff 104 and usedwhen the user is stationary. When the user moves, the pump isdisconnected and the gas reservoir 102 supplies the gas to theinflatable cuff 104.

In some embodiments the gas reservoir 102 includes an identifier thatidentifies the gas reservoir 102 to the patient monitor 106. Theidentifier can be implemented using one or more memory chips or RFIDSlocated on the gas reservoir and/or one or more circuit elements, suchas resistors, capacitors, inductors, op-amps, etc. The identifier caninclude additional information regarding the gas reservoir 102, such asthe type of gas reservoir, manufacturing date and/or location, storagecapacity or amount of gas that the gas reservoir 102 can hold, thequantity of gas in the gas reservoir, PSI levels, usage data, expirationdates, product histories, etc.

The patient monitor 106 can use the identifier to determine whether touse the gas reservoir 102, whether the gas reservoir 102 is compatiblewith the patient monitor 106, or whether the reservoir 102 is from anauthorized supplier. The identifier can be unique for each gas reservoir106 or for a set of gas reservoirs 102. In some embodiments, theidentifier indicates that the gas reservoir can be used with the patientmonitor 106. In certain embodiments, only gas reservoirs 102 with aparticular identifier are used with the patient monitor 106.Accordingly, gas reservoirs 102 that do not include the particularidentifier can be rejected and/or ignored by the patient monitor 106. Inan embodiment, an emergency use override may allow for measurements, ora specific number of measurements in an emergency situation, even when,for example, the identifier does not indicate an authorized supplier butis otherwise safe for use.

It is to be understood that other techniques exist for implementing thegas reservoir 102 without departing from the spirit and scope of thedescription. For example, the gas reservoir 102 can be implemented usingthe central gas line of a building, such as a hospital or otherhealthcare facility. Alternatively, the gas reservoir 102 can beimplemented using a bulb, bladder, pump, or the like. In still furtherembodiments, the foregoing alternatives may serve as backup options ifthe reservoir 102 is empty or otherwise not functional.

The inflatable cuff 104 includes a bladder and fills with gas in amanner controlled by the patient monitor 106 or manually, and is used toat least partially obstruct the flow of blood through a wearer's arteryin order to measure the wearer's blood pressure. The inflatable cuff 104can be attached to a wearer's arm or other location, and can be inflatedautomatically (e.g., via intelligent cuff inflation) or manually toobtain blood pressure data. Blood pressure data can include any type ofsignal received from a sensor sufficiently responsive to blood pressureto provide an indicator thereof to a user. Blood pressure data can be inthe form of pressure sensor data, auditory sensor data, and the like.

The inflatable cuff 104 can further include a wireless transmitter forwireless communication with the patient monitor 106. Alternatively, theinflatable cuff can include cables for sending and receiving informationto and from the patient monitor 106. The inflatable cuff can receive gasfrom a gas reservoir 102 via a gas pathway. Furthermore, the inflatablecuff can include a release valve for releasing the gas stored in theinflatable cuff once inflated. The release valve can be actuatedelectronically by the patient monitor 106 or manually by a user. In someembodiments, the release valve can be used when the pressure in theinflatable cuff 104 reaches unsafe levels or when the inflatable cuff104 has been inflated beyond a threshold period of time. In certainembodiments, the release valve can be actuated electronically using PWMsignals. In some embodiments, the inflatable cuff 104 is a disposablecuff that can be discarded after a one or a few uses. In certainembodiments, the inflatable cuff 104 can be reused many times andcleaned or sterilized between uses.

A sensor 108 can be placed in close proximity to the inflatable cuff 104to monitor the inflatable cuff 104 during inflation and deflation.Alternatively, the sensor 108 can be located in the patient monitor 106along a gas pathway between the gas reservoir 102 and inflatable cuff104, or at some other location where it is able to collect sufficientdata for the patient monitor 106 to determine the blood pressure of thewearer.

The sensor 108 can be a pressure sensor or an auditory sensor. In oneembodiment, the sensor 108 communicates signals responsive to thepressure in the inflatable cuff 104 to the patient monitor 106 via wiredor wireless communication. The patient monitor uses the signal todetermine a blood pressure measurement or change in blood pressure ofthe wearer. The patient monitor 106 can additionally use the pressuremeasurements to determine if the pressure in the inflatable cuff 104 isabove a threshold or is at an unsafe level. If the pressure in theinflatable cuff 104 is above a threshold or is at an unsafe level, thepatient monitor 106 can actuate an emergency release valve to deflatethe inflatable cuff 104. In an embodiment where the sensor 108 is anauditory sensor, the sensor 108 can be used to detect Korotkoff sounds.In one embodiment, the sensor 108 comprises a stethoscope.

In an embodiment, the patient monitor 106 includes a display device 110,a user interface 112, and a microprocessor or microcontroller orcombination thereof 114. The patient monitor 106 can further include anumber of components implemented by the microprocessor 114 for filteringthe blood pressure data received from the sensor 108 and determining theblood pressure of the wearer. The patient monitor 106 can be a dedicateddevice for determining blood pressure and other physiologicalparameters, a portable electronic device configured to execute a programor application that determines blood pressure and other physiologicalparameters, or can be part of a larger patient monitoring device, suchas those devices described in U.S. patent application Ser. No.09/516,110, titled “Universal/Upgrading Pulse Oximeter,” filed Mar. 1,2000 (MASIMO.162C1); U.S. patent application Ser. No. 12/534,827, titled“Multi-Stream Data Collection System For Noninvasive Measurement OfBlood Constituents,” filed Aug. 3, 2009 (MLHUM.002A); U.S. patentapplication Ser. No. 12/497,523, titled “Contoured Protrusion ForImproving Spectroscopic Measurement Of Blood Constituents,” filed Jul.2, 2009 (MLHUM.007A); U.S. patent application Ser. No. 12/882,111,titled “Spot Check Monitor Credit System,” filed Sep. 14, 2010(MLHUM.022A); U.S. patent application Ser. No. 13/308,461, titled“Handheld Processing Device Including Medical Applications For MinimallyAnd Non Invasive Glucose Measurements,” filed Nov. 30, 2011 (MLHUM.039A)and U.S. patent application Ser. No. 11/366,995, titled “MultipleWavelength Sensor Equalization,” filed Mar. 1, 2006 (MLR.003A). Each ofwhich is incorporated by reference herein.

In some embodiments, the patient monitor 106 is configured tocommunicate with the inflatable cuff 104 and/or the gas reservoir 102via wired or wireless communication, such as LAN, WAN, Wi-Fi, infra-red,Bluetooth, radio wave, cellular, or the like, using any number ofcommunication protocols. The patient monitor 106 can further beconfigured to determine blood pressure measurements of a wearer when theinflatable cuff 104 is being inflated with gas from the gas reservoir102, during deflation of the inflatable cuff 104, or a combination ofboth. The patient monitor 106 can use the microprocessor 114, thefiltering component, and blood pressure monitoring component todetermine the blood pressure measurements. The blood pressuremeasurements determined by the patient monitor 106 can be displayed onthe display 110. In addition, the display 110 can display blood pressuredata and filtered blood pressure data in the form of plots of thepressure of the inflatable cuff and plots of the pressure oscillationsin the inflatable cuff 104 caused by blood flowing through an artery ofthe wearer. Furthermore, the patient monitor 102 can calculate and thedisplay 110 can display additional physiological parameters, such asheart rate, perfusion, oxygen saturation, respiration rate, activityinformation, temperature, and the like, combinations thereof or thetrend of any of the above.

The user interface 112 can be used to allow a user to operate thepatient monitor 106 and obtain the blood pressure measurements and/orother physiological parameters. Furthermore, the user interface 112 canallow a user to set or change any number of configuration parameters.For example, using the user interface 112, a user can determine what isdisplayed on the display 110, such as the blood pressure measurementsduring inflation and/or deflation, additional physiological parameters,the pressure plots, and/or other physiological parameters, etc.Furthermore, the user interface 112 can allow a user to set whatmeasurements of what parameters the patient monitor 106 should take. Forexample, the user can set the configuration parameters to take bloodpressure measurements only during inflation or deflation. Alternatively,the user can use the user interface 112 to set the configurationparameters to take blood pressure measurements during inflation anddeflation and then use both measurements to determine an appropriateblood pressure. In addition, using the user interface 112, the user candetermine how often the patient monitor 106 takes blood pressuremeasurements, or other physiological parameter measurements. The userinterface 112 can further be used for any other type of configurationparameters that can be set or changed by a user. In some embodiments,the user interface 112 is implemented as an application of a portableelectronic device.

In some embodiments, the patient monitor 106 monitors the use of the gasreservoir. To monitor the use of the gas reservoir 102, the patientmonitor can monitor the number of times that the gas reservoir 102 isused to fill the inflatable cuff 104, the amount of time that the gasreservoir 102 is supplying gas, current pressure levels within the gasreservoir 102, and the like.

The patient monitor 106 can store usage data of the gas reservoir 102 ina memory device located on or in the gas reservoir 102. In someembodiments, the memory device is the identifier discussed previously.In certain embodiments, the memory device is located in the patientmonitor 106 or some other location, and a unique identifier of the gasreservoir 102 can be used to correlate a particular gas reservoir 102with its usage data.

Each time the gas reservoir 102 is used to inflate the inflatable cuff104, the patient monitor 106 can update the usage data. In someembodiments, the usage data reflects a total number of instances inwhich the gas reservoir has been used to inflate the cuff 104. Incertain embodiments, the usage data reflects the amount of time that thegas reservoir 102 has been supplying gas and the rate at which the gashas been supplied. Further embodiments can use any combination of theembodiments described herein.

Using the number of times that the gas reservoir has been used to fillthe inflatable cuff 104 and other data regarding the gas reservoir 102,the patient monitor 106 can determine when the gas reservoir 102 willrun out of gas and/or the number of remaining uses. In certainembodiments, the patient monitor 106 uses the storage capacity of thegas reservoir 102 and the amount of gas used to fill the inflatable cuff104 to determine the number of times the gas reservoir can be used tofill the inflatable cuff 104 before it should be replaced. In someembodiments, the patient monitor 106 calculates the total amount of timethe gas reservoir 102 is able to output gas before it should be replacedbased on the storage capacity and the rate of flow of the gas. Thepatient monitor 106 can also account for any change to the rate of flow.Additional methods can be used to calculate whether the gas reservoir102 should be replaced. For example, a pressure sensor can be used todetermine the pressure levels within the gas reservoir 102.

When the usage data indicates that the capacity of the gas reservoir 102is about to be (or has been) met, the patient monitor 106 can alert auser that the gas reservoir 102 should be replaced. The patient monitor106 can alert a user by sounding an alarm, flashing a light, sending anemail, text message, fax, page, or the like to a user.

In an embodiment where many canisters may be in circulation with one ormore monitors, the monitor may use a canister ID to track usages fordifferent canisters, such as, for example, the identifier. Inembodiments where each canister includes accessible memory storage, theusage information stored in such memory may be updated by the monitor orcanister during use.

FIG. 1B illustrates a block diagram of gas pathways between differentcomponents of the patient monitoring system 100. As describedpreviously, the patient monitoring system 100 can include a gasreservoir 102, an inflatable cuff 104, a patient monitor (not shown), apressure sensor 108, a flow valve 120, an emergency shutoff 122, and gaspathways 124. The gas from the gas reservoir 102 travels via the gaspathways 124 and valve 120 to the inflatable cuff 104.

The flow valve 120 can direct the gas from the gas reservoir 102 to thecuff 104 or to an exit pathway. During deflation of the cuff 104, theflow valve can direct the gas from the cuff 104 to the exit pathway. Insome embodiments, the flow valve is controlled using PWM signals. Thepressure sensor 108 measures the pressure within the gas pathway as wellas the changes in pressure due to the blood pressure of the wearer. Theemergency shutoff 122 can be used to quickly deflate the cuff 104 asdesired. The components illustrated in FIG. 1B can be located indifferent positions. For example, the pressure sensor 108 and emergencyshutoff 122 can be located on or in the cuff 104.

FIG. 2 illustrates a patient monitoring system 200 similar to thepatient monitoring system 100 of FIG. 1. Similar to the patientmonitoring system 100 of FIG. 1, the patient monitoring system 200 ofFIG. 2 includes a gas reservoir 202, an inflatable cuff 204, a patientmonitor 206, and a sensor 226 a like gas pathway between the reservoir202 and cuff 204. In addition, the patient monitoring system 200includes the gas pathway having a number of gas pathway segments 210,214, 218 and valves 212, 216, 222 facilitating the movement of gasthroughout the system. The gas reservoir 202, the inflatable cuff 204,the patient monitor 206, the valve 216, and the sensor 226 cancommunicate using wired or wireless communication. Cables 228 can beused to facilitate communication between the various components of thepatient monitoring system 200. The various components can be connectedto each other or connected to a central location, such as the patientmonitor 206. Alternatively, the cables 228 can be removed and thepatient monitor 202 can communicate with the other components of thepatient monitoring system via wireless communication.

As mentioned previously with reference to FIG. 1, the gas reservoir 202can be implemented using one or more gas tanks of any number ofdifferent sizes. In addition, the gas reservoir 202 can be located inthe same room as the wearer or can be located at a remote location, suchas in a different room or different building from the wearer. In such anembodiment, the gas pathway runs from the wearer to the remote locationwhere the gas reservoir 202 is located. In addition, the gas reservoir202 can be filled with any number of different gases prior to use withthe wearer 218. In other words, the gas reservoir 202 can be filled withgas prior to installation with the other components of the patientmonitoring system 200. In one embodiment, the gas reservoir 202 isfilled with a compressed gas.

Furthermore, in an embodiment, the gas from the gas reservoir 202 can beused to generate electricity for the patient monitoring system 200. Asmall turbine can be located near the opening of the gas reservoir 202,along the gas pathway, or near an opening of the inflatable cuff 204. Asthe gas flows by the turbine and into the inflatable cuff 202, theturbine rotates. The rotation of the turbine can be used to generateelectricity for the patient monitoring system 200. The electricity canbe fed to the patient monitor 206 so that the patient monitor 206 canprocess received signals and determine output measurements for the bloodpressure of the wearer as the inflatable cuff inflates. Another turbinecan be located near the release valve 224 of the inflatable cuff 204 orthe gas pathway segment 220. When the release valve 224 of theinflatable cuff 204 is opened or the valve 216 is actuated, the exitinggas causes the turbine to rotate, thereby generating electricity. Thegenerated electricity can be fed to the patient monitor 206, allowingthe patient monitor to process received signals and determine outputmeasurements for the blood pressure of the wearer as the inflatable cuff204 deflates.

Using the gas reservoir 202 to inflate the inflatable cuff 204 cansignificantly reduce the ambient noise caused by the patient monitoringsystem, resulting in a quieter environment for the wearer. In addition,the gas reservoir 202 can supply gas at an approximately constantpressure and rate. Thus, the patient monitoring system 200 can inflatethe inflatable cuff at an approximately constant rate without theauditory and electrical interfering noise of a motor or pump, resultingin a cleaner signal for the patient monitor 206. Furthermore, by usingthe gas reservoir 202, the patient monitor can measure the wearer'sblood pressure during inflation of the inflatable cuff 204.

By measuring the blood pressure during inflation of the inflatable cuff,the patient monitoring system 200 can measure the blood pressure in lesstime and using less pressure. Furthermore, measuring blood pressureduring inflation of the inflatable cuff can reduce, and in someembodiments completely remove, the amount of time that the artery isoccluded, allowing for more frequent blood pressure readings and reduceddiscomfort for the patient.

The gas reservoir 202 is operatively connected with the inflatable cuff204 via the regulator 208, gas pathway segments 210, 214, 218 and valves212, 216. The gas pathway and gas pathway segments 210, 214, 218 can bemade of any air-tight material, such as a plastic tube, metal, cloth,combinations or the like. Gas from the gas reservoir 202 flows throughthe gas pathway segments 210, 214, 218 to inflate the inflatable cuff204. In an embodiment, the regulator 208, the gas pathway segments 210,214, 218 and the valves 212, 216, 222 control the direction and rate ofgas flow throughout the patient monitoring system 200. The regulator208, which can also be a valve, located near the opening of the gasreservoir 202 controls the pressure of the gas exiting the gas reservoir202 and along the gas pathway segment 210. The valve 212 controls thepressure of the gas exiting gas pathway segment 210 and along gaspathway segments 214, 218 to the inflatable cuff 204. The regulator 208and valve 212 can be configured as a two-stage pressure regulator andused to maintain an approximately constant pressure of gas entering theinflatable cuff 204. The approximately constant pressure of gas mayadvantageously lead to an approximately constant rate of inflation ofthe inflatable cuff 204. The regulator 208 and valve 212 can beconfigured to maintain any number of pressure levels in the gas pathwaysegments 210, 214, 218. In one embodiment, the regulator 208 and valve212 are configured to maintain a pressure of approximately 6 PSI (poundsper square inch) along the gas pathway segment 214 and gas pathwaysegment 218.

The valve 216 located along the gas pathway segments 210, 214, 218 canbe used to control the direction of the gas flow throughout the patientmonitoring system 200. In an “on” configuration, the valve 216 allowsthe gas to pass from the gas pathway segment 214 to the gas pathwaysegment 218 into the inflatable cuff 204. In an “off” configuration, thevalve 216 closes the gas pathway between the gas reservoir 202 and theinflatable cuff 204 and opens a gas pathway from the inflatable cuff 204and gas pathway segment 218 to the gas pathway segment 220 and throughvalve 222. The valve 216 can be actuated electronically using thepatient monitor 206 or manually by a user. For safety, the defaultposition for the valve 216 can be the “off” configuration. In this way,should there be any malfunctions, the inflatable cuff 204 can deflate.In an embodiment, the valve 216 is a three-way valve. The valve 216 canbe implemented in a number of different ways without departing from thespirit and scope of the description.

The valve 222 is similar in most respects to the valve 212 and cancontrol the rate at which gas is allowed to exit the inflatable cuff204. The valves 212, 222 can be implemented as any number of differentvalves, such as globe valve, butterfly valves, poppet valves, needlevalves, proportional valves, etc., or any other type of valve capable ofoperating as a variable restriction to the gas flow. Furthermore, thevalves 212, 222 can be actuated manually by a user or electronically bythe patient monitor 206.

A number of alternative embodiments exist for implementing the patientmonitoring system 200 without departing from the spirit and scope of thedescription. For example, the valve 216 can be located in the inflatablecuff 204 or nearby. In addition, the valves 216, 222 can be removedcompletely. In this embodiment, the patient monitor 206 can actuate theregulator 208 and/or valve 212 to inflate the inflatable cuff 204. Whenthe inflatable cuff 204 is to be deflated, the patient monitor 206 canactuate the regulator 208 and/or valve 212 a second time, as well asactuate the release valve 224. Alternatively, two valves can be used inplace of the valve 216. One valve can be used to allow gas to flow fromthe gas reservoir to the inflatable cuff. The second valve can be usedto release gas from the inflatable cuff. The two valves can be actuatedindependently or at the same time. Furthermore, the two valves can beactuated electronically using the patient monitor 206 or manually by auser.

In addition, the regulator 208 and valve 212 can be implemented usingany number of different configurations. For example, regulator 208 andvalve 212 can be implemented as two separate devices as shown or as onesingle device. Alternatively, the patient monitoring system 200 can beimplemented using only the regulator 208 and/or the valve 212. Inaddition, the regulator 208 or any of the valves 212, 216, 222 canfurther include a pressure gauge to identify the pressure levels of thegas. In addition, the regulator 208 and each valve 212, 216, 222 cancommunicate with the patient monitor 206 via wired or wirelesscommunication.

As mentioned previously, the inflatable cuff 204 is used to at leastpartially obstruct an artery of a wearer to measure the wearer's bloodpressure. In an embodiment, the inflatable cuff 204 partially obstructsthe wearer's artery without occluding, or completely closing, the arteryto determine a blood pressure measurement of the wearer.

In one embodiment, the inflatable cuff 204 includes a bladder, a releasevalve 224 and an attachment mechanism. The bladder contains the gasreceived from the gas reservoir 202, via the gas pathway and can be madeof any material capable of holding gas. For example, the bladder can bemade of plastic, cloth, or some other airtight material. Furthermore,the bladder can be configured to hold gas at any number of PSI levels.In one embodiment, the bladder is capable of holding gas at about 4 PSI.However, it is to be understood that the bladder can hold gas at greaterthan or less than about 4 PSI. An opening in the bladder allows the gasfrom the gas reservoir to enter exit.

The attachment mechanism allows the inflatable cuff 204 to be attachedto a wearer. The attachment mechanism can be made of hook and loop typefasteners, cloth, a clip, flexible materials, water wicking materials,or other material that allows the inflatable cuff 204 to attach to awearer. The release valve 224 can be actuated manually by a user,electronically by the patient monitor 206, or automatically based on apredefined threshold pressure level. The release valve 224 can be usedto release the gas from the inflatable cuff 204 when the pressurereaches a predetermined threshold or unsafe level, or when theinflatable cuff 204 has been inflated above a threshold pressure for apredetermined amount of time.

The sensor 226 can be located on the inside of the inflatable cuff 204,at the patient monitor 206, along the gas pathway segments 210, 214, 218or along a separate gas pathway segment, as illustrated in FIG. 2.Alternatively, the sensor 226 can be located at the wearer's ear, wrist,finger, or other location. When obtaining blood pressure data from thefinger, wrist, or ear less pressure is needed to identify the bloodpressure of a wearer, which increases the amount of blood pressuremeasurements that can be taken by the gas reservoir 202. As mentionedpreviously, the sensor 226 can be used to collect blood pressure datafrom the wearer. In an embodiment, the sensor 226 is a pressure sensorcapable of measuring the pressure of the inflatable cuff 204 as theinflatable cuff 204 inflates and/or deflates. In another embodiment, thesensor 226 is an auditory sensor used to identify Korotkoff sounds asthe inflatable cuff 204 inflates and/or deflates. The cables 228 can beused to communicate the information from the sensor 226 to the patientmonitor 206. Alternatively, the sensor 226 can use a wirelesstransmitter to communicate the blood pressure data to the patientmonitor 206.

As mentioned previously, the patient monitor 206 includes a display 230capable of displaying the diastolic and systolic pressure 232 of thewearer as determined by the patient monitor 206 during inflation and/ordeflation. Furthermore, the patient monitor 206 can display the bloodpressure measured during inflation and deflation, thereby allowing theuser to compare the values. The display 230 of the patient monitor 206can further be configured to display pressure plots, which can includeplots of the blood pressure data 236A and filtered blood pressure data236B. The plots of the blood pressure data 236A can include the pressureof the inflatable cuff 204 over time, and the plots of the filteredblood pressure data 236B can include the pressure oscillations observedby the sensor, as will be described in greater detail below withreference to FIGS. 3A-3C. In addition, the patient monitor 206 can beconfigured to display additional physiological parameters 234 as furtherillustrated on the display device 208. These physiological parameterscan include, but are not limited to, heart rate, oxygen saturation,perfusion, glucose measurements, and the like. In addition, the patientmonitor 206 can include configuration parameters to control the display230, as well as the patient monitor 206. Using the configurationparameters, a user can initiate blood pressure measurements of thewearer 218 to control the patient monitor 206.

The patient monitor can also include a user interface for setting orchanging the configuration parameters. The configuration parameters canbe use to set the frequency and type of blood pressure measurementstaken as well as the manner in which to display the measurements. In anembodiment, a periodic or other schedule can be set to obtainmeasurement; for example, times of day, duration between, or the likemay be used to set measurement schedules. In other embodiments, themonitor may monitor other parameters, such for example, oxygensaturations, where a predetermined change in the other parameterstriggers a blood pressure measurement.

The configuration parameters can determine how often a blood pressuremeasurement should be taken, whether it should be taken duringinflation, deflation or both. Furthermore the configuration parameterscan determine how the patient monitor calculates the blood pressuremeasurements, such as using the inflationary blood pressuremeasurements, the deflationary blood pressure measurements, arbitratingbetween the two, or using a combination such as any a statisticalcombination of the two or additional measurements like, for example,past measurements. Furthermore, the configuration parameters candetermine how the blood pressure measurements should be displayed. Forexample, the configuration parameters can dictate that only inflationaryblood pressure measurements, deflationary blood pressure measurements,the more reliable measurement, or combinations thereof are to bedisplayed. Furthermore, the configuration parameters can determine ifand how the pressure plots, and other physiological parameters are to bedisplayed.

In addition, the patient monitor 206 can be configured to determineblood pressure measurements while the inflatable cuff 204 is inflatingand without occluding the wearer's artery. The patient monitor 206 canbe configured to actuate a valve connected to the gas reservoir 202,causing gas to flow from the gas reservoir 202 to the inflatable cuff204. As the inflatable cuff 204 inflates, the patient monitor 206 cancalculate the diastolic pressure and systolic pressure of the wearer 218using any number of techniques, as described in greater detail belowwith reference to FIGS. 4A and 4B. For example, the patient monitor 206can calculate the diastolic pressure and systolic pressure by measuringoscillations of blood flow in an artery or auditory cues as theinflatable cuff 204 inflates and/or deflates. By measuring the wearer'sblood pressure during inflation of the inflatable cuff, both thediastolic and systolic pressure can be determined by partiallyobstructing the wearer's artery and without occluding it. Once thesystolic pressure is measured, the patient monitor can actuate the valve216 or a release valve 224 on the inflatable cuff 204 to release the gaswithin the inflatable cuff 204.

FIGS. 3A-3G illustrate an embodiment of a patient monitoring system 300configured to be worn by a user. FIG. 3A is a front perspective view ofan embodiment of the patient monitoring system 300. The patientmonitoring system 300 includes a patient monitor 302, an inflatable cuff304, and a chamber 306 to retain a gas reservoir 308. The inflatablecuff 304 and chamber 306 can be removably attached to the patientmonitor 302. The patient monitor 302, chamber 306, and gas reservoir 308will be described in greater detail below, with reference to FIGS.3B-3G.

The inflatable cuff 304 is similar to the inflatable cuffs described ingreater detail above, with respect to FIGS. 1A, 1B, and 2. In theillustrated embodiment, the inflatable cuff 304 includes an arm band andcan be wrapped around an arm of a user. The inflatable cuff 304 caninclude one or more attachment surfaces 326A, 326B to maintain theinflatable cuff 304 in a relatively fixed position around the arm of theuser. In the illustrated embodiment, the attachment surfaces 326A, 326Bare located on either side of the patient monitor 302. In someembodiments, the attachment surfaces 326A, 326B are located on one sideof the patient monitor 302, or there is only one attachment surface. Theattachment surfaces 326A, 326B can be made from a variety of differentmaterials, such as, but not limited to, hook and loop type fasteners,buttons, snaps, hooks, latches, tape, or other device capable ofmaintaining the inflatable cuff 304 in a substantially fixed positionabout the user.

Although not illustrated in FIG. 3A, the patient monitoring system 300can further include one or more sensors capable of detecting one or morephysiological parameters of the user. The sensors can communicate withthe patient monitor 302 via wired or wireless communication using avariety of protocols, including, but not limited to, TCP/IP, Bluetooth,ANT, ANT+, USB, Firewire, etc. For example, the patient monitoringsystem 300 can include one or more pressure sensors, auditory sensors,pulse oximetry sensors, thermometers, accelerometers, and/or gyroscopes.The physiological parameters detected by the various sensors caninclude, but are not limited to, blood pressure, heart rate,temperature, perfusion, respiration, activity rate, etc. One or more ofthe sensors can be located within the inflatable cuff 304 or elsewhereon the user. For example, an auditory sensor can be located on the chestof the user to collect respiration data about the user. Another auditorysensor can be located within the inflatable cuff 304 to collect bloodpressure data.

FIG. 3B is a front perspective view of an embodiment of the patientmonitor 302 and the chamber 306. In the illustrated embodiment, thepatient monitor 302 includes a display 310, a communications linkindicator 312, and user interface objects 314, 316. In some embodiments,the patient monitor 302 can further include a power monitor thatdetermines the amount of power remaining for use by the patient monitor302. When the patient monitor is battery-operated, the power monitor candetermine the amount of time or the number of blood pressuremeasurements that remain before the batteries are to be replaced orrecharged.

The patient monitor 302 can be a device dedicated to the measurement ofphysiological parameters or can be a portable electronic deviceconfigured to measure physiological parameters. In some embodiments, thepatient monitor 302 is a portable electronic device, such as asmartphone, tablet, or the like, running a program or applicationconfigured to calculate physiological parameters based on signalsreceived from the sensors.

The patient monitor 302 receives data from one or more sensors andprocesses the data to extract physiological parameters of the user. Forexample, the patient monitor 302 can receive data from a pressure and/orauditory sensor and calculate the patient's blood pressure. In someembodiments, the patient monitor 302 uses accelerometer and gyroscopedata to calculate an activity level of the user.

The patient monitor 302 can also provide activity recommendations basedon the physiological parameters of the user. For example, the patientmonitor can use the patient's height, weight, age, sex, blood pressurereadings, heart rate, etc., to recommend a physical activity such aswalking, running, or cycling. Furthermore, during an activity thepatient monitor 302 can provide recommendations as to whether thepatient should increase or decrease their activity levels.

The display 310 is an embodiment of the display 110 described above withreference to FIG. 1A. The display 310 can be implemented using a touchscreen, LCD screen, LED screen, or other type of screen and can be usedto display one or more physiological parameters, plot diagrams, or userinterface information, etc. The display 310 can be any number ofdifferent sizes, and in some embodiments, covers a majority of one sideof the patient monitor 302. In the illustrated embodiment, the display310 displays heart rate data 318, blood pressure data 320, 322, and ahealth indicator 324. However, additional physiological parameters canbe displayed, such as, but not limited to, temperature, respirationdata, perfusion index data, plethysmograph data, metabolism data, suchas calories/hour, etc.

The health indicator 324 can be based on the heart rate data 318, bloodpressure data 320, 322, other physiological parameters, or anycombination thereof, and can indicate an overall well being of a user.For example, if the patient monitor 302 determines that the bloodpressure data 320, 322 is normal, an arrow can point to the middle ofthe health indicator 324 or the health indicator 324 can be green, etc.If the patient monitor 302 determines that the blood pressure data 320,322 is high or low, the arrow can point to the top or bottom health orthe health indicator 324 can be red or blue, etc. Similarly, otherphysiological parameters or a combination of physiological parameterscan be used by the health indicator 324.

The communication link indicator 312 can be used to indicate whether acommunication link is established with one or more devices, such as thesensors, a computer, a portable electronic device, etc. Thecommunication link indicator 312 can change colors or blink depending onthe status of the communication link. For example, the communicationlink indicator 312 can blink during initialization, can turn green onceconnected, and turn red when a signal is lost or is below a thresholdlevel.

The user interface objects 314, 316 can be implemented using hardware orsoftware. For example, the user interface objects 314, 316 can bebuttons or keys, form part of the display 310, or any combinationthereof. The user interface objects 314, 316 can be used to interfacewith the patient monitor 302. For example, the user interface object 314can be used to select one or more options from the patient monitor 302,such as which physiological parameters to display, how to display thephysiological parameters, toggle between which sensors to use, viewhistorical physiological parameter data, etc. In addition, the userinterface objects 314, 316 can be used to determine the frequency withwhich blood pressure measurements should be taken. For example, usingthe user interface objects 314, 316 the patient monitor 302 can beconfigured to automatically take blood pressure measurementssequentially as determined by a user, or can be configured to take onlyone blood pressure measurement before requiring additional input fromthe user. For example, in some embodiments, by pushing or holding down auser interface object, the patient monitor 302 will automatically togglebetween a single measurement mode and a sequential measurement mode.Furthermore, the user interface objects 316 can be used to scrollthrough one or more options displayed on the display 310. Other userinterface objects can be used as desired.

With continued reference to FIG. 3B, the chamber 306 can be in physicalcontact with the patient monitor 302. In some embodiments, the patientmonitor 302 fits into a pre-formed case, which also contains the chamber306. In certain embodiments, the patient monitor 302 includes attachmentmechanisms to connect with the chamber 306. The attachment mechanismscan include, but are not limited to, clips, screws, screw holes, bars,snaps, buttons, and the like. The gas reservoir 308 fits into thechamber 308 as illustrated and as will be described in greater detailwith reference to FIG. 3C. Furthermore, the chamber 306 can be adjustedto fit different sized gas reservoirs 308.

FIG. 3C is a back perspective view of the patient monitor 302 andchamber 306. The illustrated embodiment further includes a gas reservoirinterface 307 as part of the chamber 306. The gas reservoir interface307 interacts with the gas reservoir 308 to maintain the gas reservoirwithin the chamber 306. The gas reservoir interface 307 can include alocking mechanism that prevents the use of unapproved or unauthorizedgas reservoirs 208. The locking mechanism can be a mechanical orelectronic locking mechanism.

A mechanical locking mechanism can include many forms, such as threads,a clamp, lock and key designs, etc. For example, in some embodiments,the gas reservoir interface 307 can includes threads that complementthreads of the gas reservoir 308. Accordingly, the gas reservoir 308 canbe screwed into the chamber 306 using the gas reservoir interface 307.In some embodiments, gas reservoirs 308 that include a different numberof threads, a different design of threads, or that do not includethreads will not properly interface with the gas reservoir interface307. In certain embodiments, a clamp can act as the locking mechanism tokeep the gas reservoir 308 in place. In certain embodiments, themechanical locking mechanism can be in the form of a proprietaryconnector. The gas reservoir interface 307 can include a particularphysical layout that is uniquely designed to interface with approved orauthorized gas reservoirs 308, similar to a lock and key design.

The locking mechanism can also be implemented as an electronic lockingmechanism. The electronic locking mechanism of the gas reservoirinterface 307 can include an electronic interface that allows thepatient monitor 302 to communicate with the gas reservoir 308. Theelectronic interface can include a memory chip, processor, RFID,resistor, or other circuit elements that can interface with electronicson the gas reservoir 308. Authorized or approved gas reservoirs 308 caninclude the circuit elements that can unlock the electronic lockingmechanism of the gas reservoir interface 307 and allow the gas reservoir308 to be used with the patient monitor 302.

The illustrated embodiment also includes an interface 330 attached tothe patient monitor 302 and used to maintain the patient monitor 302 inclose proximity to the inflatable cuff 304. The recess 332 of interface330 can complement a portion of the cuff 304 to lock the patient monitor302 in place with the cuff 304. Screws 334 can be used to maintain theinterface 330 attached to the patient monitor 302.

FIGS. 3D and 3E are side perspective views of the patient monitor 302and chamber 308. FIGS. 3F and 3G are top and bottom perspectives of thepatient monitor and chamber 308, respectively. With reference to FIG.3G, the patient monitor 302 can include an electronic interface 336,such as a USB or mini-USB port. The electronic interface 336 can be usedto communicate with another electronic device, such as a computer orportable electronic device. FIG. 3G further illustrates that the chamber306 can be rotated forwards and backwards as desired. For example, thechamber 306 can be physically attached to the patient monitor 302 via apivot that allows the chamber 306 to swing about one or more axes. Thepivot can be implemented using a hinge, ball-and-socket joint, link,pin, spring, swivel, bolt, and the like. The pivot can also include alocking mechanism that can lock the chamber 306 in a certain positionwith respect to the patient monitor 302. The locking mechanism can beimplemented using a clamp, ratchet, pin, grooves within a link, pin,spring, or bolt, and the like. In this way, the chamber 306 can berotated to a preferred position and then locked in place for use. Forexample, a user can adjust the chamber 306 so that it fits snuglyagainst their arm, or other limb, and then lock the chamber in thatposition so that it stays in its position when the user moves.

As mentioned previously, the display 230, can be configured to displayadditional information regarding the wearer. FIGS. 4A-3C are plotdiagrams illustrating embodiments of various plots that can be displayedby the display 230, 310. The plots in FIGS. 4A-3C are plot diagramsillustrating some embodiments of the pressure at the inflatable cuff204, including the oscillations of pressure, observed by the sensor 226during inflation and deflation.

Plot 401A is a plot diagram illustrating an embodiment of the pressureof the inflatable cuff 204 during inflation and deflation, which canalso be referred to as blood pressure data. The x-axis of plot 401Arepresents the number of samples taken by the patient monitor 206 overtime. The patient monitor 206 can be configured to take samples at anynumber of increments to achieve a desired data resolution. For example,the patient monitor 206 can sample the inflatable cuff every second,millisecond, microsecond, etc. Although illustrated in increments ofsamples, time can also be used for the x-axis 402. The y-axis 404A ofplot 401A represents the pressure level, in mmHg, of the inflatable cuff204. The line 412 represents the pressure level of the inflatable cuff204 over time.

Prior to point 408, signals on the line 412 represent electronic noisecaused by the environment or the patient monitoring system 200. At point408, the valve 216 is actuated. The valve 216 can be actuatedelectronically by the patient monitor 206 or manually by a user. Onceactuated, gas from the gas reservoir 202 begins to inflate theinflatable cuff 204 at a rate determined by a user electronically usingthe patient monitor 206 or manually using the regulator 208 and/or valve212. In one embodiment, the inflation rate is an approximately constantrate, which leads to an approximately constant increase in pressure inthe inflatable cuff. The sensor 226 reads the rise in pressure in theinflatable cuff 204, as indicated by the rise in line 412 of the plot401A. Thus, from point 408 to point 410, the inflatable cuff is in aninflation mode and is inflating.

At point 410, the valve 216 is actuated again, ending the inflation ofthe inflatable cuff 204. Although illustrated at 200 mmHg, the point 410can be located at any desired pressure level. In one embodiment, the 216valve is actuated when the measured pressure level within the inflatablecuff 204 is greater than the expected systolic pressure of the wearer.The expected systolic pressure of the wearer can be determined byprevious blood pressure measurements, historical information, clinicaldata from one or more wearers, or the like. In one embodiment, the point410 changes between blood pressure measurements. For example, theinflatable cuff can be configured to inflate to 200 mmHg for the firstmeasurement. If it is determined during the first measurement that thewearer's systolic pressure is measurably less than 200, then during theproximate measurement, the inflatable cuff 204 can be inflated to alower pressure. Varying the pressure level to which the inflatable cuff204 inflates can conserve gas. Likewise, if the wearer's measuredsystolic pressure is greater than the expected systolic pressure, theinflatable cuff 204 can be inflated to a greater pressure during theproximate measurement. Alternatively, the valve 216 can be actuated oncethe inflatable cuff 204 reaches any desired or predefined pressurelevel, such as 160 mmHg, 200 mmHg, 400 mmHg, etc.

In some embodiments, in addition to ending the inflation of theinflatable cuff, actuating the valve 216 also begins a deflation mode ofthe inflatable cuff. For example, actuating the valve 216 can close thegas pathway between the gas reservoir 202 and the inflatable cuff 204and open the gas pathway between the inflatable cuff 204 and ambientair, allowing the gas to exit the inflatable cuff 204. Once the valve216 is actuated, the inflatable cuff 204 deflates leading to a decreasein pressure within the inflatable cuff 204. Actuating the valve 216, aswell as the valve 222 can be configured so that the pressure within theinflatable cuff 204 decreases at any desired rate. In one embodiment,the pressure within the inflatable cuff 204 decreases at anapproximately constant rate. Additional blood pressure measurements canbe taken during the deflation of the inflatable cuff 204, as describedin greater detail below with reference to FIGS. 5A and 5B.

The patient monitor 206 can calculate the blood pressure of the wearerat any time during inflation and/or deflation, once it has receivedsufficient blood pressure data. In some embodiments, the patient monitor206 can calculate the diastolic pressure followed by the systolicpressure during inflation of the inflatable cuff 204. In certainembodiments, the patient monitor can calculate both diastolic andsystolic pressure simultaneously once the valve 216 is actuated orduring inflation, once the patient monitor 206 has sufficient bloodpressure data. The patient monitor 206 can alternatively wait untiladditional measurements are taken during the deflation of the inflatablecuff 204 before calculating the diastolic and systolic pressure. In thisway, the patient monitor can compare or arbitrate the diastolic andsystolic measurements during inflation and deflation of the inflatablecuff 204 to achieve greater reliability in the measurements.

With continued reference to FIG. 4A, the plot 401B is a plot diagramillustrating an embodiment of the change in pressure in the inflatablecuff 204 due to blood flow in the artery during inflation and deflationof the inflatable cuff 204. In one embodiment, the line 414 is obtainedby filtering the plot 401A and normalizing the data based on the changein pressure due to the inflation and deflation of the inflatable cuff204 and can be referred to as filtered blood pressure data. The plot401B of the pressure oscillations due to the blood flow in the artery ofthe wearer, or filtered blood pressure data, can be displayed on thedisplay 230, 310 along with the plot 401A, the blood pressure readings,and/or other physiological parameters. Similar to plot 401A, the x-axis402 of plot 401B represents the number of samples taken by the patientmonitor 206 over time. The y-axis 404B of plot 401B representsnormalized changes in pressure in the inflatable cuff 204.

As illustrated in the plot 401B, when the valve 216 is actuated at point408, the inflatable cuff 204 inflates and exerts pressure against thewearer's artery. As the inflatable cuff 204 exerts pressure against thewearer's artery, the sensor 226 is able to detect the variations inpressure in the inflatable cuff 204 due to blood flow within the artery,which are also referred to as pressure variations or pressureoscillations. The pressure oscillations are illustrated in plot 401A assmall deviations or bumps in the line 412.

As further illustrated by the plot 401B, as the inflatable cuff 204continues to inflate, the artery becomes increasingly obstructed,leading to greater pressure variations observed by the pressure sensor,which leads to greater oscillations in the line 414. With continuedinflation of the inflatable cuff, the variations in pressure eventuallybegin to decrease as the blood flow becomes occluded. At point 410, thepressure exerted by the inflatable cuff completely occludes the artery.As mentioned previously, in one embodiment, once the artery is occluded,the valve 216 is actuated allowing the gas to exit the inflatable cuff204 and the inflatable cuff 204 to deflate. In another embodiment, thevalve 216 is actuated prior to the occlusion of the artery.

As further illustrated by the plot 401, as the inflatable cuff 204begins to deflate, the oscillations of the pressure observed by thepressure sensor 226 again begin to increase significantly as blood flowin the artery increases. As the inflatable cuff 204 further deflates,the pressure exerted on the artery decreases leading to a decrease inpressure variation observed by the pressure sensor 226. Eventually, theinflatable cuff 204 exerts little to no pressure on the artery, and theblood flow in the artery has little to no effect on the pressure in theinflatable cuff 226. The patient monitor 206 uses the characteristics ofthe oscillations of pressure due to blood flow through an artery of thewearer, such as the slope of the oscillations and/or the magnitude oramplitude of the oscillations, to determine the blood pressure. Thepatient monitor 206 can use the blood pressure data obtained duringinflation and/or deflation of the inflatable cuff to determine the bloodpressure.

In one embodiment, to determine the blood pressure during inflation, thepatient monitor identifies the pressure in the inflatable cuff at whichthe largest magnitude oscillation, also referred to as the maximumdeflection point or largest amplitude oscillation, during inflation isdetected. In the illustrated embodiment, the pressure monitor identifiesthe largest magnitude oscillation at point 430. The pressure in theinflatable cuff at which the largest magnitude oscillation duringinflation is detected approximately coincides with the systolic bloodpressure of the wearer. In one embodiment, the patient monitor alsoidentifies the pressure in the inflatable cuff at which the largestslope in the oscillations prior to the largest magnitude oscillationduring inflation is detected. In the illustrated embodiment, thepressure monitor identifies the largest slope in the oscillations priorto the largest magnitude oscillation at point 432. The largest slope inthe oscillations prior to the largest magnitude oscillation duringinflation approximately coincides with the diastolic pressure of thewearer.

In addition, the patient monitor can determine the blood pressure of thewearer during deflation. In one embodiment, to determine the bloodpressure during deflation, the patient monitor identifies the largestmagnitude oscillation during deflation (point 434 in the illustratedembodiment). The patient monitor further identifies the pressure in theinflatable cuff at which the largest slope in the oscillations prior tothe largest magnitude oscillation during deflation is detected (point436 in the illustrated embodiment). The largest slope in theoscillations prior to the largest magnitude oscillation during deflationapproximately coincides with the systolic pressure of the wearer. Thepatient monitor also identifies the pressure in the inflatable cuff atwhich the largest slope in the oscillations after the largest magnitudeoscillation during deflation (point 436 in the illustrated embodiment).The largest slope in the oscillations after the largest magnitudeoscillation during approximately deflation coincides with the diastolicpressure of the wearer.

A number of alternate methods exist for determining blood pressureduring inflation and deflation of the inflatable cuff. For example,during deflation the patient monitor can calculate the systolic bloodpressure as the pressure at which the oscillations become detectable andthe diastolic pressure as the pressure at which the oscillations are nolonger detectable. Alternatively, the patient monitor can calculate themean arterial pressure first (the pressure on the cuff at which theoscillations have the maximum amplitude). The patient monitor can thencalculate the diastolic and systolic pressures based on theirrelationship with the mean arterial pressure. Additional methods can beused without departing from the spirit and scope of the description. Forexample, pressure values at locations other than the largest magnitudeoscillation or maximum deflection point and largest slope can also beused.

Plots 401A and 401B further illustrate the potentially adverse effectsignal noise can have on the blood pressure measurements. Asillustrated, signal noise is detected at least twice in line 414 priorto inflation. The detected signal noise in at least one instance exceedsthe maximum deflection point during inflation. In addition, the signalnoise may also contain the largest slope prior to the maximumdeflection. In either event, if the signal noise is not accounted for,the patient monitor 206 is in danger of calculating diastolic andsystolic pressures of the wearer at points other than during inflationor deflation. In some embodiments, based on the amount and magnitude ofsignal noise detected, the patient monitor can assign confidence levelsto the blood pressure measurements. Based on line 414, the patientmonitor 206 can place a lower confidence level in the blood pressuremeasurement during inflation due to the observed signal noise.

As mentioned above, the plots 401A, 401B can both be displayed on thedisplay 230, 310 of the patient monitor 206, 302. The plots 401A, 401Bcan be displayed simultaneously or consecutively. In addition the plots401A, 401B can be displayed along with the diastolic pressure andsystolic pressure as measured by the patient monitor 206. Furthermore,the measured diastolic pressure and systolic pressure during inflationcan be displayed along with the measured diastolic pressure and systolicpressure during deflation. In addition, the patient monitor 206 canfurther display additional physiological parameters measured by thepatient monitor 206.

FIGS. 4B and 4C include plot diagrams illustrating additionalembodiments of the pressure of the inflatable cuff 204 during inflationand deflation. Plots 403A and 405A correspond to plot 401A, and plots403B and 405B correspond to plot 401B. Similar to plots 401A and 401B,plots 403A, 403B, 405A, and 405B illustrate the inflation of theinflatable cuff 204 beginning at point 408 and ending at point 410. Inaddition the deflation of the inflatable cuff begins at point 410 inplots 403A, 403B, 405A, and 405B.

Plots 403A and 403B further illustrate signal noise being exhibited atdifferent points throughout the lines 416 and 418. The first observedsignal noise occurs near the beginning of the lines 418 and anotheroccurs near the end. Similar to the oscillations due to blood flow inthe artery, signal noise is exhibited as small displacements on the line416 and oscillations in the line 418. As illustrated, unless accountedfor, the signal noise occurring in plots 403A and 403B can have anadverse affect on blood pressure measurements due at least to theirmagnitude. The first detected signal noise results in the maximumdeflection point prior to deflation and the last detected signal noiseresults in the maximum deflection point after deflation. In embodiments,where maximum deflection points are used, if inflation and deflation arenot demarcated appropriately or if signal noise is not accounted for,the patient monitor 206 can erroneously determine the blood pressuremeasurements based on the signal noise.

The plot 403B further illustrates an example where a blood pressuremeasurement taken during inflation can in some instance have a higherconfidence level than the blood pressure measurement taken duringdeflation. As mentioned previously, during inflation, the diastolicpressure can be determined as the pressure at which the largest slope inline 418 prior to the maximum deflection point during inflation occurs(point 442 in the illustrated embodiment). The systolic pressure can becalculated as the pressure at which the maximum deflection point of line418 occurs during inflation (point 440 in the illustrated embodiment).Upon deflation, the systolic pressure is calculated as the pressure atwhich the largest slope in line 418 prior to the maximum deflectionpoint (point 444 in the illustrated embodiment) during deflation occurs(point 446 in the illustrated embodiment). Similarly, the diastolicpressure is calculated as the pressure at which the largest slope inline 418 after the maximum deflection point during deflation occurs(point 448 in the illustrated embodiment). As illustrated in plot 403B,the maximum deflection point during deflation can be difficult toidentify, which can make it difficult to calculate the diastolic andsystolic pressure of the wearer accurately. Accordingly, the confidenceplaced in the blood pressure measurement during deflation can berelatively low compared to the confidence level placed in the bloodpressure measurement during inflation. Accordingly, the patient monitor204 can determine that the blood pressure measurement taken duringinflation is likely more accurate. In addition, depending on the amountand magnitude of the signal noise detected, the patient monitor 206 candetermine that neither blood pressure measurement reaches a thresholdconfidence level and that blood pressure measurements should be retaken.

Plots 405A and 405B illustrate yet another example of blood pressuremeasurements taken during inflation and deflation of the inflatable cuff204. As illustrated, signal noise is detected near the beginning oflines 420 and 422, resulting in oscillations observed in line 422. Asmentioned previously, if not accounted for, the signal noise canadversely affect the blood pressure measurements during inflation.However, in the line 422, the maximum deflection point prior todeflation occurs during inflation. Thus, the signal noise at thebeginning of the line 422 should not affect the blood pressuremeasurements. Plots 405A and 405B further illustrate an example wherethe blood pressure measurement taken during inflation can have a similarconfidence level as the confidence level of the blood pressuremeasurement taken during deflation. As illustrated, the line 418exhibits a distinctive maximum amplitude during inflation (point 450 inthe illustrated embodiment) and during deflation (point 454 in theillustrated embodiment). In the illustrated embodiment, the patientmonitor calculates the largest slope during inflation as the slope atpoint 452. During deflation, the patient monitor calculates the largestslop prior to the maximum amplitude at point 456 and the largest slopfollowing the maximum amplitude at point 458.

FIG. 5A is a flow diagram illustrating an embodiment of a process 500Afor measuring blood pressure during inflation of an inflatable cuff 204.As illustrated in FIG. 5A, the process 500A begins at block 502 byactuating a valve, which allows gas to flow from a gas reservoir 202 tothe inflatable cuff 204, causing the inflatable cuff 204 to inflate. Thevalve can be located near an opening of the gas reservoir 202, at somepoint along the gas pathway or at the inflatable cuff 204. In oneembodiment, multiple valves 212, 216 and/or regulators 208 can beincluded between the gas reservoir 202 and the inflatable cuff 204. Eachvalve and/or regulator can be actuated prior to inflating the inflatablecuff 204. The valve(s) can be actuated manually by a user orelectronically by a patient monitor 206. For example, a user canmanually open the valve 216 to allow gas to flow from the gas reservoir202 to the inflatable cuff 204. The user can open the valve in a waythat allows for the inflation of the inflatable cuff 204 at anapproximately constant rate of inflation. A regulator 208 can also beused to achieve the approximately constant rate of inflation.Alternatively, a patient monitor 206 in communication with the gasreservoir can actuate the valve 216, allowing the gas to flow from thegas reservoir 202 to the inflatable cuff 206. Communication from thepatient monitor 206 can occur by wired or wireless communication, suchas a LAN, WAN, Wi-Fi, infra-red, Bluetooth, radio wave, cellular, or thelike, using any number of communication protocols.

To actuate the valve, an input to the patient monitor 206 such as abutton can be used. Alternatively, the patient monitor can automaticallyactuate the valve once the patient monitor is turned on or based on oneor more configuration parameters. For example, the patient monitor canbe configured to determine the blood pressure of a wearer once everytime period. The timer period can be configured as any period of time,such as 6 minutes, 15 minutes, 60 minutes, etc. In yet anotherembodiment, the patient monitor 206 determines if the inflatable cuff isattached to a wearer. If the patient monitor 206 determines that theinflatable cuff is attached to a wearer, the patient monitor 206 canactuate the valve at predefined time intervals. Any number of methodscan be used to determine if the inflatable cuff is attached to a wearer.For example, the patient monitor 206 can determine whether theinflatable cuff is attached to a wearer using infra-red sensors,pressure sensors, capacitive touch, skin resistance, processor pollingor current sensing or the like.

Once the inflatable cuff 204 is inflating, the patient monitor 206receives blood pressure data from the sensors, as illustrated in block504. The blood pressure data can be obtained at the inflatable cuff 204using any number of different sensors or methods. For example, apressure sensor can be used to identify the air pressure due to theinflation and deflation of the inflatable cuff 204. The pressure sensorcan be located at the inflatable cuff, the patient monitor 206, at somepoint along the gas pathway, or some other location where it is capableof measuring the pressure of the inflatable cuff 204. Alternatively, anauditory sensor communicatively coupled to the patient monitor 206 canbe used to detect Korotkoff sounds, similar to the method used formanual determination of blood pressure using a stethoscope.

At block 506, the patient monitor 206 filters the blood pressure data.Filtering the blood pressure data can reduce the effects of, orcompletely remove, environmental noise and/or the electrical noise foundwithin the patient monitoring system. Furthermore, during filtering, thepatient monitor 206 can normalize the blood pressure data to account forthe changes in pressure due to the inflation and deflation of theinflatable cuff. In one embodiment, after filtering the blood pressuredata, only the pressure oscillations in the inflatable cuff 204 due toblood flow in an artery of the wearer remain, and in some instancessignal noise. Upon filtering the blood pressure data, the patientmonitor 206 can determine the blood pressure of the wearer, asillustrated in block 508.

The patient monitor 206 can determine the blood pressure using anynumber of different methods as described above with reference to FIGS.4A-3C. For example, the patient monitor 206 can determine the bloodpressure of the wearer using the slopes and/or amplitude of the pressureoscillations, the mean arterial pressure, and/or the Korotkoff sounds.

Once the patient monitor 206 determines the blood pressure of thewearer, the patient monitor 206 can actuate a valve to stop gases fromflowing from the gas reservoir to the inflatable cuff, as illustrated inblock 510. In one embodiment, the valve is a three-way valve 216 andactuating the valve to stop the gases from flowing from the gasreservoir to the inflatable cuff also opens the gas pathway segment 220to release the gas from the inflatable cuff.

Fewer, more, or different blocks can be added to the process 500Awithout departing from the spirit and scope of the description. Forexample, the patient monitor 206 can filter the blood pressure data todetermine the diastolic pressure first. As the diastolic pressure isbeing calculated, the patient monitor 206 can continue receiving andfiltering the blood pressure data to determine the systolic pressure. Inan embodiment, the patient monitor can determine the blood pressurewithout filtering the blood pressure data. In addition, a user candetermine the blood pressure measurements without the use of the patientmonitor 206. In an embodiment, a user using a stethoscope can determinethe diastolic and systolic pressure during inflation of the inflatablecuff without filtering the blood pressure data.

As mentioned previously, by measuring the blood pressure duringinflation of the inflatable cuff 204, the blood pressure of the wearercan be measured in less time and using less pressure. Furthermore,because the artery is occluded for less time, or not occluded at all,the blood pressure can be measured more frequently.

FIG. 5B illustrates a flow diagram of a process 500B for measuring bloodpressure during deflation of an inflatable cuff. At block 550, theinflatable cuff 204 is inflated. In one embodiment, the inflatable cuff204 is inflated using gas from a gas reservoir 202. Using the gas fromthe gas reservoir 202, the inflatable cuff 204 can be inflated veryquickly leading to a relatively short wait time before blood pressuremeasurements can be taken.

As the inflatable cuff 204 inflates, the patient monitor determineswhether a threshold pressure has been reached, as illustrated in block552. The threshold pressure can be any pressure level and can varybetween blood pressure measurements. Furthermore, the threshold pressurecan be determined based on previous blood pressure measurements,historical information, clinical data from one or more wearers, or thelike. In one embodiment, the threshold pressure is above an expectedsystolic pressure of the wearer. In another embodiment, the thresholdpressure is above an expected occlusion pressure or the pressure atwhich the artery is occluded. The inflation can be initiated in a mannersimilar to that described above with reference to FIG. 5A. If thepatient monitor 206 determines that the threshold pressure has not beenreached, the inflatable cuff 204 continues to inflate. However, if thepatient monitor 206 determines that the threshold pressure has beenreached, the process moves to block 554.

At block 554, the patient monitor 206 actuates the valve to initiatedeflation of the inflatable cuff 206. In one embodiment, the valve is athree-way valve similar to valve 216 of FIG. 2, such that the inflationof the inflatable cuff 204 ends at the same time deflation begins. Oncethe deflation of the inflatable cuff 204 begins, the process moves toblock 556 and the patient monitor receives blood pressure data, filtersthe blood pressure data 558, and determines blood pressure 560. Greaterdetail regarding receiving blood pressure data 556, filtering the bloodpressure data 558 and determining blood pressure is described above withreference to blocks 504-408 of FIG. 5A.

Fewer, more, or different blocks can be added to the process 500Bwithout departing from the spirit and scope of the description. Forexample, the patient monitor 206 can determine the systolic pressureprior to receiving the blood pressure data or filtering the bloodpressure data to determine the diastolic pressure. In addition, theprocess 500B can be implemented without the use of the patient monitor206. For example, a user can receive blood pressure data via astethoscope. The user can determine the blood pressure of the wearerusing Korotkoff sounds, and can also determine the blood pressure of thewearer without filtering the blood pressure data. Furthermore, process500A and 500B can be combined and measurements taken during inflationand deflation of the inflatable cuff. Furthermore, the measurementstaken during deflation of the inflatable cuff can be used to verify theblood pressure readings taken during inflation of the inflatable cuff204.

FIG. 6 is a flow diagram illustrating another embodiment of a process600 implemented by the patient monitor for measuring blood pressure of awearer. FIG. 6 is similar in many respects to FIGS. 5A and 5B. Forexample, blocks 602-508 of FIG. 6 correspond to blocks 502-408 of FIG.5A, respectively. Furthermore, blocks 614-520 correspond to blocks554-460 of FIG. 5B, respectively.

As described above with reference to FIG. 5A and illustrated in blocks602-508, the patient monitor 206 actuates a valve to initiate inflation,receives blood pressure data during inflation, filters the bloodpressure data, and determines the blood pressure of the wearer. Upondetermining the blood pressure of the wearer, the patient monitorassigns a confidence level to the blood pressure measurements, asillustrated in block 610. The confidence level assigned can bedetermined in any number of ways. For example, based on the amount andmagnitude of the noise observed in the blood pressure data, the patientmonitor can assign the confidence level. Alternatively, if an anomaly inthe blood pressure data is detected or if the blood pressure datadeviates beyond a threshold level a lower confidence level can beassigned to the blood pressure measurements. In an embodiment, priormeasurements or other expectations or trend information may be used todetermine confidence levels.

At determination block 612, the patient monitor 206 determines if theconfidence level assigned to the inflationary blood pressuremeasurements are above a threshold confidence level. The thresholdconfidence level can be determined based on previous blood pressuremeasurements, historical information, clinical data from one or morewearers, or the like. If the confidence level assigned to the bloodpressure measurements during inflation exceeds the threshold confidencelevel, the patient monitor 206 outputs the inflationary blood pressuremeasurements, as illustrated in block 628. The inflationary bloodpressure measurements can be output to a display, a printer, anotherpatient monitor, etc. Once output, the patient monitor 206 can actuate avalve to deflate the inflatable cuff 204 at a rate greater than would beused if the blood pressure measurements were taken during deflation.Alternatively, the patient monitor 206 can deflate the inflatable cuff204 at the same rate as when blood pressure measurements taken duringdeflation.

If on the other hand, the confidence level assigned to the inflationaryblood pressure measurements is less than the threshold confidence level,then the patient monitor can actuate the valve to initiate deflation ofthe inflatable cuff, as illustrated in block 614. As blocks 614-520correspond to blocks 554-460 of FIG. 5B, additional details with respectto blocks 614-520 are provided above with reference to FIG. 5B.

Upon determining the blood pressure during deflation, the patientmonitor 206 can assign a confidence level to the deflationary bloodpressure measurements, as illustrated in block 622 and described ingreater detail above with reference to block 610. Upon assigning theconfidence level to the deflationary blood pressure measurements, thepatient monitor 206 determines if the confidence level exceeds athreshold confidence, as illustrated in determination block 624, similarto the determination made in block 612. If the patient monitor 206determines that the confidence level assigned to the deflationary bloodpressure measurements does not exceed the confidence threshold, thepatient monitor 206 can output an error, as illustrated in block 626.The error can indicate that neither the inflationary blood pressuremeasurements nor the deflationary blood pressure measurements exceededthe confidence threshold. In addition, the patient monitor 206 canrecommend that additional blood pressure measurements be taken.

If on the other hand, the patient monitor determines that the confidencelevel assigned to the deflationary blood pressure measurements exceedsthe confidence threshold, the patient monitor outputs the deflationaryblood pressure measurements, as shown in block 628.

Fewer, more, or different blocks can be added to the process 600 withoutdeparting from the spirit and scope of the description. For example, inan embodiment, the patient monitor 206 automatically returns to step 602upon outputting the error or determining that the confidence level didnot exceed the confidence threshold, and repeats the process 600. In yetanother embodiment, the patient monitor 206 outputs the error as well asthe blood pressure measurements having the highest confidence level.

FIG. 7 is a flow diagram illustrating yet another embodiment of aprocess 700 implemented by the patient monitor 206 for measuring bloodpressure of a wearer. At block 702, the patient monitor 206 receivesconfiguration parameters. The configuration parameters can be set by auser, another patient monitor, or preset. The configuration parameterscan include when to measure blood pressure, how to calculate thediastolic and systolic blood pressure, what measurements to display,confidence thresholds, etc. For example the configuration parameters caninclude whether to take blood pressure measurements during inflation,deflation, or both. In addition, the configuration parameters caninclude information regarding what process to use to determine the bloodpressure measurements. For example, the patient monitor can determinethe blood pressure measurements using the measured arterial pressure,the slopes of the pressure oscillations, maximum deflection points ofthe filtered blood pressure data, or other criteria. The configurationparameters can also include the confidence level to be used indetermining whether the blood pressure measurements should be accepted.Furthermore, the configuration parameters can include what bloodpressure measurements are to be output and how to determine which bloodpressure measurements to output. For example, the configurationparameters can dictate that only blood pressure measurements having aconfidence level greater than a threshold are to be output, or that theblood pressure measurements having the highest threshold are to beoutput. Additionally, the configuration parameters can dictate that bothblood pressure measurements, average blood pressure measurements, andthe like are to be output. Furthermore, the configuration parameters caninclude the frequency with which the blood pressure measurements are tobe taken.

At block 704, the patient monitor initiates inflation based on thereceived configuration parameters. For example, the configurationparameters can dictate the rate at which the inflatable cuff 204 is tobe inflated using the gas reservoir 202. In an embodiment, theinflatable cuff 204 is inflated at an approximately constant rate. Inanother embodiment, the inflatable cuff is not inflated at anapproximately constant rate. In an embodiment, the inflatable cuff 204is inflated in a relatively short amount of time or at a very high rateof inflation. In another embodiment, the inflatable cuff 204 is inflatedmore slowly.

At block 706 the inflationary blood pressure measurements are determinedby the patient monitor 706 based on the configuration parameters. Theconfiguration parameters can dictate whether and what method to use indetermining the inflationary blood pressure measurements. Furthermore,the configuration parameters can dictate whether the blood pressure datais filtered and how. In an embodiment, the configuration parametersdictate that the inflationary blood pressure measurements are not to betaken based on the inflation rate. In another embodiment, the patientmonitor determines the inflationary blood pressure measurements based onthe slope and magnitude of the oscillations of the filtered bloodpressure data during inflation based on the configuration parameters. Inaddition, the patient monitor can set confidence levels and performother operations based on the configuration parameters.

Upon determining the inflationary blood pressure measurements, thepatient monitor initiates deflation of the inflatable cuff 204 based onthe configuration parameters. The configuration parameters can dictatethe time and rate at which the inflatable cuff 204 deflates. Forexample, the configuration parameters can dictate a threshold pressurethat when reached initiates the deflation. The threshold pressure can bebased on personal information of the wearer or general safety levels. Inan embodiment, the patient monitor initiates deflation based on athreshold pressure being reached for a predefined period of time basedon the configuration parameters. In another embodiment, the patientmonitor initiates deflation once the inflationary blood pressuremeasurements are taken.

Upon initiating deflation, the patient monitor determines deflationaryblood pressure measurements based on one or more configurationparameters, as illustrated in block 710. As discussed previously, withreference to block 706 the configuration parameters can include anynumber of parameters that determine if and how the deflationary bloodpressure measurements are taken, as well as if and how the bloodpressure data is filtered. In addition, the patient monitor can setconfidence levels and perform other operations based on theconfiguration parameters.

Upon determining the deflationary blood pressure measurements, thepatient monitor arbitrates blood pressure measurements based on theconfiguration parameters. The patient monitor can arbitrate the bloodpressure measurements based on any number of configuration parameters.For example, the patient monitor can arbitrate the blood pressuremeasurements based on the highest confidence level or whether athreshold confidence level was reached. Furthermore, the patient monitorcan arbitrate based on expected values, previous values, averages or thelike. Alternatively, the patient monitor can select both theinflationary and deflationary blood pressure measurements.

At block 714, the patient monitor outputs the results of the arbitrationbased on the configuration parameters. The output can include theinflationary blood pressure measurements, the deflationary bloodpressure measurements, both or a combination of the two. The output canfurther include additional information, such as inflation rate,deflation rate, average blood pressure measurements depending on whetherthey were determined during inflation or deflation, etc.

Fewer, more, or different blocks can be added to the process 700 withoutdeparting from the spirit and scope of the description. For example,based on the blood pressure measurements, the configuration parameterscan be changed and the process 700 can begin again.

Depending on the embodiment, certain acts, events, or functions of anyof the methods described herein can be performed in a differentsequence, can be added, merged, or left out all together (e.g., not alldescribed acts or events are necessary for the practice of the method).Moreover, in certain embodiments, acts or events can be performedconcurrently, e.g., through multi-threaded processing, interruptprocessing, or multiple processors, rather than sequentially.

The various illustrative logical blocks, modules, circuits, andalgorithm steps described in connection with the embodiments disclosedherein can be implemented as electronic hardware, computer software, orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. The described functionalitycan be implemented in varying ways for each particular application, butsuch implementation decisions should not be interpreted as causing adeparture from the scope of the disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein can be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), an application specific integrated circuit (ASIC), afield programmable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general purpose processor can be a microprocessor, but in thealternative, the processor can be any conventional processor,controller, microcontroller, or state machine. A processor can also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theembodiments disclosed herein can be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module can reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such the processorcan read information from, and write information to, the storage medium.In the alternative, the storage medium can be integral to the processor.The processor and the storage medium can reside in an ASIC. The ASIC canreside in a user terminal. In the alternative, the processor and thestorage medium can reside as discrete components in a user terminal.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment.

While the above detailed description has shown, described, and pointedout novel features as applied to various embodiments, it will beunderstood that various omissions, substitutions, and changes in theform and details of the device or process illustrated can be madewithout departing from the spirit of the disclosure. As will berecognized, certain embodiments of the inventions described herein canbe embodied within a form that does not provide all of the features andbenefits set forth herein, as some features can be used or practicedseparately from others. The scope of the inventions is indicated by theappended claims rather than by the foregoing description. All changeswhich come within the meaning and range of equivalency of the claims areto be embraced within their scope.

1. A blood pressure monitoring system wearable by a monitored patient,the system comprising: a housing; an inflatable cuff configured toencompass a limb of a monitored patient; a removable gas reservoirstoring pressurized gas; a chamber positioning the gas reservoir; a gaspathway between the gas reservoir and the inflatable cuff operable toinflate and deflate the cuff using the pressurized gas; at least onesensor outputting a signal responsive to a pressure of the gas insidethe cuff; and a processing device configured to receive said signal fromsaid at least one sensor, process said signal and determine one or moreblood pressure measurements during at least one of inflation anddeflation; wherein said housing is operably associated with said chamberand said cuff to allow said blood pressure monitoring system to worn onsaid limb of said monitored patient.
 2. The system of claim 1, whereinsaid processing device comprises a monitor and further comprising ahousing operably associated with said processing device to allow saidprocessing device to also be worn on said limb.
 3. The system of claim1, wherein said processing device comprises a personal computing device.4. The system of claim 1, wherein said processing device comprises aphone executing one or more applications capable of said processing andsaid determining.
 5. The system of claim 1, wherein said processingdevice controls said inflation and said deflation of said cuff throughcommunication with one or more valves in said gas pathway.
 6. The systemof claim 1, wherein said processing device determines the blood pressuremeasurements during inflation.
 7. The system of claim 6, wherein saidprocessing device determines a systolic pressure as a magnitudeoscillation of the signal and a diastolic pressure as a slope of thesignal prior to the magnitude oscillation.
 8. The system of claim 7,wherein the magnitude oscillation is the largest magnitude oscillationof the signal during inflation and the slope is the largest slope of thesignal prior to the largest magnitude oscillation.
 9. The system ofclaim 1, wherein said processing device determines the blood pressuremeasurements during deflation.
 10. The system of claim 9, wherein saidprocessing device determines a systolic pressure as a pressure of theinflatable cuff corresponding to a first slope of the signal prior to amagnitude oscillation and a diastolic pressure as a pressure of theinflatable cuff corresponding to a second slope of the signal followingthe magnitude oscillation.
 11. The system of claim 10, wherein themagnitude oscillation is the largest magnitude oscillation of the signalduring deflation, the first slope is the largest slope of the signalprior to the largest magnitude oscillation, and the second slope is thelargest slope of the signal following the largest magnitude oscillation.12. The system of claim 1, wherein said processing device is furtherconfigured to: determine the one or more blood pressure measurementsduring inflation; assign a confidence level to the one or more bloodpressure measurement; determine whether the confidence level is greaterthan a threshold confidence level; and upon determining that theconfidence level is not greater than the threshold confidence level,determine additional one or more blood pressure measurements duringdeflation.
 13. The system of claim 1, wherein said processing deviceimplements a measurement protocol.
 14. The system of claim 13, whereinsaid measurement protocol includes periodic measurements.
 15. The systemof claim 14, wherein said measurement protocol monitors otherphysiological parameters and initiates a blood pressure measurement whenother physiological parameters exhibit a predetermined behavior.
 16. Thesystem of claim 14, wherein the other physiological parameter responsiveto oxygen saturation.
 17. The system of claim 1, wherein said processingdevice communicates with electronics associated with said gas reservoir18. The system of claim 17, wherein the electronics associated with thegas reservoir indicate whether the gas reservoir is authorized.
 19. Thesystem of claim 17, wherein the electronics associated with the gasreservoir indicate gas reservoir usage.
 20. The system of claim 19,wherein indicate updated data responsive to usage is written to theelectronics associated with said gas reservoir.
 21. The system of claim17, wherein the electronics associated with the gas reservoir indicatereservoir characteristics.
 22. The system of claim 1, wherein saidprocessing device is configured to display of waveform on a displaydevice.
 23. The system of claim 22, wherein the waveform is responsiveto arterial pulse.
 24. The system of claim 22, wherein the displaydevice is multi-lingual.
 25. The system of claim 22, wherein the displaydevice includes a wellness indicator.
 26. A method of determining one ormore blood pressure measurements, the method comprising: determining oneor more blood pressure measurements during at least one of inflation anddeflation of an inflatable cuff, wherein determining the one or moreblood pressure measurements during inflation comprises: inflating aninflatable cuff connected to an arm of a patient using a replaceable gasreservoir of a portable inflation system, receiving a signal from asensor indicative of a pressure inside the inflatable cuff, filteringthe signal, identifying a maximum magnitude of the filtered signalduring inflation of the inflatable cuff, and associating a pressure ofthe inflatable cuff during approximately the identified maximummagnitude with a first systolic pressure; wherein determining the one ormore blood pressure measurements during deflation comprises: deflatingan inflated inflatable cuff connected to the arm of the patient, whereinthe inflatable cuff is inflated using the replaceable gas reservoir ofthe portable inflation system, receiving a signal from a sensorindicative of a pressure inside the inflatable cuff, filtering thesignal, identifying a maximum magnitude of the filtered signal duringdeflation of the inflatable cuff, a maximum slope of the filtered signalprior to the maximum magnitude, and a maximum slope of the filteredsignal following the maximum magnitude, and associating a pressure ofthe inflatable cuff during approximately the identified maximum slope ofthe filtered signal prior to the maximum magnitude with a secondsystolic pressure; and outputting at least one of the first systolicpressure and the second systolic pressure to a display device.
 27. Themethod of claim 26, further comprising: determining the one or moreblood pressure measurements during inflation of the inflatable cuff;assigning a confidence level to the one or more blood pressuremeasurements; determining whether the confidence level is greater than athreshold confidence level; and upon determining that the confidencelevel is not greater than the threshold confidence level, determiningadditional one or more blood pressure measurements during deflation ofthe inflatable cuff;
 28. The method of claim 26, further comprising:determining whether the pressure within the replaceable gas reservoir isgreater than a threshold pressure level; and replacing the replaceablegas reservoir when the pressure is not greater than the thresholdpressure level.
 29. The method of claim 26, further comprisingcommunicating with electronics of the replaceable gas reservoir.
 30. Themethod of claim 29, wherein the electronics indicate whether thereplaceable gas reservoir is authorized.
 31. The method of claim 29,wherein the electronics indicate usage of the replaceable gas reservoir.32. The method of claim 29, wherein updated data responsive to usage ofthe replaceable gas reservoir is written to the electronics of thereplaceable gas reservoir.
 33. The method of claim 29, wherein theelectronics associated with the gas reservoir indicate reservoircharacteristics.
 34. The method of claim 29, further comprisingdisplaying a waveform of the signal on a display device.